When parents can't see their kid's report card in their account, it usually means the parent has a duplicate account and the report card published to that account instead of the one the parent uses.
To see which account a report card published to, be in School view, top tab Global, side tab Favorite. Click on Report Delivery Recipient.
In the column "Desc", it will tell you the name of the student.
In the column "User > Login", it will tell you the family account that the report card has been published to. Once I get back, I can merge the duplicate accounts, but in the meantime, please check with the parent if they are logging into this account or a different one.
Scroll to the right and look for the File column. Download the report card to share with the parent.